X-ray diffraction and Mössbauer spectroscopy of the core/shell iron/iron oxide system

Abstract Iron–iron oxide nanocomposites obtained by inert gas condensation techniques have been studied by X-ray diffraction and Mossbauer spectroscopy as a function of particle size in the 5–25 nm range, i.e. as a function of the oxide volume fraction. The oxide (spinel) phase is characterised by small grain size and high atomic disorder. The thermal relaxation in the supposedly ferrimagnetic order of the oxide is reduced by magnetic polarisation of the iron core. The oxide Mossbauer spectrum has been fitted with two broad sextets with different dependence on the particle size of the hyperfine field distribution.